This invention relates to the art of ink jet cartridges used in ink jet printers and, more particularly, to an improved filter member and/or wick member associated with the outlet passage of an ink chamber of an ink jet cartridge.
It is generally known in the art to form a cartridge housing or body having one or more chambers that hold a predetermined supply of ink and from at least one of which chambers there is an outlet port including an outlet passage which receives a supply needle from an associated printer for conveying ink from the housing to a recording head or the like. It is also generally known to provide an ink absorbing member such as a body of reticulated polyethylene or melamine foam within the housing. In some arrangements, the cartridge housing is divided into multiple chambers, one of which receives the body of ink absorbing material and the other which receives free ink which migrates from its chamber into the ink absorbing material through an opening providing communication between the two chambers. The ink absorbing material controls the flow of ink as it migrates toward the outlet port.
It is generally known too, as shown for example in U.S. Pat. No. 5,488,401 to Mochizuki, et al. and U.S. Pat. No. 6,776,477 to Putman, et al. to cover the inlet end of the outlet passage through the outlet port with a filter member in the form of a plate attached to the bottom wall of the ink chamber such as by heat bonding. Heretofore, such a filter member has been of a high polymer or anti-corrosive metal including, for example, woven nylon screen material and woven stainless steel mesh preferably having a pore size of about 1-25 microns. The filter member is interposed between the outlet passage and ink absorbing member to prevent the entrance of air bubbles, contaminants, and the like from the cartridge.
It is also known as shown, for example, U.S. Pat. No. 5,619,239 to Kotaki, et al., U.S. Pat. No. 6,293,660 to Kishida, et al. and U.S. Pat. No. 6,293,663 to Koshikawa, et al. to provide the outlet passage between the entrance and exit ends thereof with a wick member in the form of a body of fibrous material or bundled fibers of a fibrous material such as polyester, nylon, polypropylene, polyethylene, cellulose, polyurethane, or the like. Other fiber material, such as metallic fiber, glass fiber and carbon fiber can also be used alone or in mixtures with the previously mentioned materials.
While the filter screen and filter materials heretofore used provide the intended filtering functions, the fibers in the woven nylon material appear to swell when used with water based inks, thus losing or reducing the intended flow characteristics. Furthermore, the stainless steel material has to be passivated in order to remove iron from the surface of the mesh, thus to expose more of the chromium and preclude rusting or corrosion of the mesh. While the stainless steel thus treated is acceptable, the passivating process is time-consuming and expensive.